What makes a critical infrastructure?
An interesting notion of understanding I got from our workshop at COOP 2014 in Nice and the conference afterwards is that an infrastructure is only then critical when its failure is noticed by humans and they are unhappy about the failure.
Alan Chamberlain had formulated that much better in his talk. Thus, there are so much more critical infrastructure things than the classic examples electricity and communication. Moreover, Internet may not always be one.
As a side note, a critical part of that notion is that it may actually consider the security of an infrastructure uncritical due to its often indirect or invisible consequences to consumers. This is even more true for privacy. That caused some discussion, very good to hear a non-ICT view on these subjects. So, thanks to all participants.